Messages in this thread | | | From | Gerrit Huizenga <> | Subject | Re: [PATCH] scheduler hints | Date | Wed, 05 Jun 2002 18:05:29 -0700 |
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In message <200206060046.g560kJi04034@mushroom.ca.boeing.com>, > : Rick Bressle r writes: > > So I went ahead and implemented scheduler hints on top of the O(1) > > scheduler. > > > Other hints could be "I am interactive" or "I am a batch (i.e. cpu hog) > > task" or "I am cache hot: try to keep me on this CPU". > > Sequent had an interesting hint they cooked up with Oracle. (Or maybe it > was the other way around.) As I recall they called it 'twotask.' > Essentially Oracle clients processes spend a lot of time exchanging > information with its server process. It usually makes sense to bind them > to the same CPU in an SMP (and especially NUMA) machine. (Probably > obvious to most of the folks on the group, but it is generally lots > better to essentially communicate through the cache and local memory > than across the NUMA bus.)
Actually, process-to-process affinity, which was later generalized as a process gang affinity.
> As I recall it made a significant difference in Oracle performance, and > would probably also translate to similar performance in many situations > where you had a client and server process doing lots of interaction in > an SMP environment.
Yep. Must be used with care, but not terribly damaging for general access. Typically arranged as a many to one linkage by the callers, which simplified the rebalancing decisions a bit. I think there was a paper written about it somewhere by Phil Krueger.
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